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Objective To compare the expression levels of pncA gene in pyrazinamide （PZA）-resistant and multidrug-resistant Mycobacterium tuberculosis before and after PZA drug stimulation， and to explore the relationship between PZA-resistant Mycobacterium tuberculosis and pncA gene expression. Methods PZA-resistant and multidrug-resistant Mycobacterium tuberculosis was cultured， and the minimal inhibitory concentration （MIC） of rifampicin and PZA was detected. The strains were cultured in medium containing 0 and 50 μg/mL PZA， and the expression level of pncA was detected by real-time fluorescence quantitative PCR. Results The MIC of PZA of 21 strains of Mycobacterium tuberculosis was ≥ 1 600 μg/mL，400-800 μg/mL for 12 strains， and 100-200 μg/mL in 5 strains，and their corresponding PZA resistance levels were defined as high，medium and low，respectively. The median MIC of rifampicin was 128， 128 and 64μg/mL， respectively. Chi-square test showed that there was no significant difference between any two groups （all P > 0.05）. According to the relative quantitative 2-ΔΔCt method， the expression levels of pncA in the high，medium and low levels of PZA drug-resistant Mycobacterium tuberculosis was 0.904（0.202， 2.653）， 1.157（0.658， 1.511） and 1.147（0.372， 1.347）， and 1.544（0.611， 3.191）， 0.846（0.421， 1.237） and 0.726 （0.225， 3.017） in the 50 μg/mL treatment group，respectively. There was no significant difference in pncA gene expression between the control and PZA drug-containing culture groups（P > 0.05）. Conclusion No significant changes are observed in the expression levels of pncA in multidrug-resistant and PZA-resistant Mycobacterium tuberculosis before and after PZA drug stimulation.

Objective To preliminarily explore whether there is a correlation between heat shock protein gene hspX and drug resistance of Mycobacterium tuberculosis （MTB） by comparing the sequence and expression of hspX in MTB with different drug resistance types. Methods Ten strains sensitive to all four first-line anti-tuberculosis drugs （S）， one drug resistance （rifampicin-resistant MTBR+， isoniazid-resistant MTBH+， streptomycin-resistant MTBS+ and ethambutol-resistant MTBE+） and multidrug resistance （MDR） to isoniazid and rifampicin were selected， respectively. The DNA and RNA of strains in each group were extracted by modified SDS lysis method and TRIzol method， respectively. The existence and expression of hspX gene were determined by PCR and RT-PCR using specific primers. PCR products were sequenced to check the forward and reverse polymorphism， and DNAman software was employed to compare the sequence with the standard strain H37Rv. The difference in the expression of hspX among MTB strains with different drug resistance types was analyzed by pairwise with the sensitive strain group as the control group. Results The specific hspX gene was successfully obtained by PCR. The hspX gene sequence was 97%-99% identical with H37Rv， and there was no significant difference. The mean expression level of hspX through relative quantitation 2-ΔΔCt in S， MDR， MTBR+， MTBH+， MTBS+ and MTBE+ strains was calculated as 0.98（0.89， 1.23）， 1.49（1.10， 2.04）， 1.41（0.55， 2.80）， 1.37（0.68， 2.71）， 0.91（0.59， 1.62）and 0.70（0.48， 1.18）， respectively. There was no significant difference in the expression of hspX among different drug-resistant strains groups when the sensitive strain group was regarded as the control group （all P > 0.05）. Conclusion The hspX gene is conserved in MTB. In natural state， there is no significant correlation between hspX gene and drug resistance of MTB.

With the increasing diversity of social media, the demand for real-time analysis of social networks continues to increase, and research on dynamic community detection has received extensive attention. Existing community detection reviews mostly focus on static community detection and the discussion of related methods, so network evolution analysis cannot be carried out. Besides, the entity data in the community are cross-substitutional and sequential. Therefore, the research status of dynamic community detection is studied, reviewed, and analyzed. First, based on the research background of complex networks, a general research framework for dynamic community detection is proposed. Then, the relevant definitions of dynamic community detection are formally expressed, and the evolution of dynamic communities at the network level and node level is analyzed in detail. According to the difference in architecture and technology, the dynamic community detection methods are summarized and classified. Combined with commonly used data sets, the static community detection algorithm is analyzed qualitatively and quantitatively with evaluation criteria. Finally, the typical application scenarios of community detection are introduced, the main challenges faced by current dynamic community detection research are discussed, and relevant solutions are put forward for dynamic communities, which outlines a clearer and comprehensive research direction for dynamic community detection research field.

Wheat is one of the most important food crops globally, and understanding the regulation of grain size is crucial for wheat breeding to achieve a higher grain yield. MicroRNAs (miRNAs) play vital roles in plant growth and development. However, the miRNA-mediated mechanism underlying grain size regulation remains largely elusive in wheat. Here, we report the characterization and functional validation of a miRNA, TamiR397a, associated with grain size regulation in wheat. The function of three TaMIR397 homoeologs was determined through histochemical β-glucuronidase-dependent assay. MiRNA expression was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the function of TamiR397a was validated through its transgenic overexpression and repression in wheat. It was found that TaMIR397-6A and TaMIR397-6B encode active TamiR397a. The expression profiling indicated that TamiR397a was differentially expressed in various tissues and gradually up-regulated during grain filling. The inhibition of TamiR397a perturbed grain development, leading to a decrease in grain size and weight. Conversely, the overexpression of TamiR397a resulted in increased grain size and weight by accelerating the grain filling process. Transcriptome analysis revealed that TamiR397a regulates a set of genes involved in hormone response, desiccation tolerance, regulation of cellular senescence, seed dormancy, and seed maturation biological processes, which are important for grain development. Among the down-regulated genes in the grains of the TamiR397a-overexpressing transgenic plants, 11 putative targets of the miRNA were identified. Taken together, our results demonstrate that TamiR397a is a positive regulator of grain size and weight, offering potential targets for breeding wheat with an increased grain yield. [ABSTRACT FROM AUTHOR]

To improve the potassium availability of feldspar at ordinary temperatures, the mechanical grinding and addition of sodium hydroxide/salts were employed to study the effects of mechanical activation and strong alkali addition on particle characteristics, water-soluble potassium, and the available potassium of feldspar. A laser particle size analyzer was utilized for the direct determination of particle size distribution (PSD) using ground samples. The Brunauer–Emmett–Teller (BET) method was employed for specific surface areas. X-ray diffraction (XRD) was employed for structural characterization, scanning electron microscopy (SEM) for morphology exploration, and energy dispersive spectroscopy (EDS) to determine the chemical composition of potassium feldspar powder. The results revealed that the mechanical activation of potassium feldspar could reduce the particle size and produce agglomerated nanoparticles in the later period. The addition of NaOH and sodium salt did not cause agglomeration, and NaOH dissolved the nanoparticles. The water-soluble potassium content of feldspar in each treatment increased during mechanical grinding, from 21.64 mg kg−1 to 1495.81 mg·kg−1, by adding NaOH 5% weight of potassium feldspar powder and to 3044.08 mg·kg−1 by adding NaOH 10% weight with effects different from those of mechanical shaking. By comparison, only 162.93 mg·kg−1 water-soluble potassium was obtained by adding NaOH 5% weight. The dissolved potassium in the former case was significantly higher than in the latter, and the addition of NaOH and sodium salts significantly enhanced the water-soluble potassium contents due to ion exchange. Furthermore, the addition of sodium hydroxide improved the water-soluble potassium due to its mechanochemical action on potassium feldspar. The mechanical energy changed the crystal structure of potassium feldspar, explaining the increase in available potassium. The addition of sodium salts did not promote change in the feldspar's structure, thereby did not raise the available potassium content. The reason for this was related to the mechanochemical action on sodium hydroxide and feldspar, which could promote the dissolution of fine particles, thereby incrementing the available potassium. [ABSTRACT FROM AUTHOR]

Safety valve is an important guarantee for nuclear power plant system. Its working environment is harsh, and medium is high-temperature corrosive. It is important to study the dynamic characteristics of nuclear safety valve under unsteady condition to improve the stability and safety of nuclear power plant piping system. Using the finite element method, mass simplification and Rayleigh method, the frequency response analysis of the safety valve and the spring is predicted to predict the seismic capacity under the earthquake load. Based on the verification of the dynamic characteristics of the valve body, the stress and strain analysis of the spring is carried out. To explore the failure condition of the safety valve spring, the lateral deviation linearity of the spring was tested and analyzed by setting up the offset test bench. The results show that the safety valve with the above analysis method can meet the working requirements under the shaking condition. The research results provide an important theoretical basis for the design and analysis of nuclear safety valves.